The present invention relates to rotary cutters, especially to cutters wherein a rotary support mounts one or more detachable blades serving to remove chips, shavings or other types of fragments from wood or the like.
It is known to utilize in a rotary wood cutter a cylindrical carrier whose peripheral surface is formed with rearwardly and inwardly inclined recesses for discrete plate-like blades and wedges which are biased by springs and serve to urge the blades against suitable holders which are secured to the carrier. It is also known to provide in such carriers suitable abutments for the rear or inner edges of the blades; the abutments may constitute integral parts of the carrier or they constitute adjustable strips which are separably mounted in the respective recesses. In many instances, the blades are secured to their holders by means of screws so that each blade constitutes with the respective holder a package or group which is removably insertable into the corresponding recess of the carrier. For example, each holder may be provided with a dovetailed projection which is receivable in a complementary groove machined into the carrier and extending in parallelism with the axis of rotation of the cutter. Reference may be had to German Offenlegungsschrift No. 2,159,033 or 2,220,003. When a blade having a dull cutting edge is to be replaced, the entire package must be removed from the corresponding recess, the blade detached from the associated holder, and a new blade fastened to such holder before the package is ready for insertion into the carrier. Prior to insertion of a package, the latter is introduced into a device wherein the position of the new blade with respect to the holder is adjusted to insure that the cutting edge of the new blade will protrude beyond the periphery of the carrier and that the extent of such protrusion will be within a desired range.
The just described mode of replacing worn blades is complicated and takes up too much time so that the cutter is idle at frequent intervals and for extended periods of time. Proposals to reduce the intervals of idleness of the cutter include the provision of spare holders which are assembled with satisfactory blades while the cutter is in use so that the replacement of a damaged or worn blade takes up only as much time as is needed to remove a holder from its recess and to insert a spare holder which is properly connected with a satisfactory blade. The utilization of spare holders contributes significantly to the initial cost of the cutter because the latter must be furnished with a number of blades and holders which greatly exceeds the number of recesses in the rotary carrier. Moreover, the workman who is in charge of replacing dull blades must be present at all times so that he cannot perform other duties in the plant where the cutter is being put to use with a large number of similar cutters or with other woodworking instrumentalities.